There will be Different Users of the system and each of them deserves a good way to communicate with the system. Systems are judged mostly by their IUs -- see http://www.cooper.com/.

* **Dorothy** is a very nice professional wooman who who wants to feel at home like a bird in it's little nest.  She does not care what computers or other machines are behing the right air in her house, she wants to be confortable right now wherever she is.  She is not very energy conservation concerned. She would never accept neither nasty-looking devices nor blue wires on her walls. A simple wireless HVAC controller would be OK if it looks sleek.

* **Jerry** installs HVAC for living. He wants to do a good job. That means no calls from customers. He likes simple, rugged modules that snap together, have a few well defined switches and never break. Software setup should not be more complicated than the ordering/billing system in the local bar. He needs very actionable information if anything goes wrong.

* **Peter** has always a lot of questions and does not mind if the answer takes more than 7 words. He wants to know all details how his HVAC works and why. He wants graphs, tables, charts. He will spend a lot of time trying to tweek his HVAC to get the best performance. He might be dangerous doing that. He even reads some parts of the user's manual if nothing else works.

* **Vadim** knows how the system works. He even remembers the most cryptic names of modules. He is not cared with an error message longer than the screen.

* **Boris** wants everything cool. He does not mind paying a lot for the system that talks to him and listens to his commands.